The field of this invention relates to a latch assembly for doors.
Door latch assemblies are used in diverse applications. Some of these applications call for doors with different backsets for the door latch to accommodate differently sized operating doorknobs or handles. The latch assemblies are desirably adaptable for use in both wood and metal doors. A modem latch generally has a tubular latch housing that is mounted in a lateral bore at the edge of the door. The latching bolt has a canted forward face that provides retraction of the bolt when the face abuts against a striker plate in the doorjamb upon closing the door. The bolt springs back into the hole of the striker plate to latch the door shut. It is desirable to incorporate a deadbolt or privacy bolt which when recessed by abutment against the striker plate prevents the latching bolt from retraction unless operated by the door knob.
In wood doors, the faceplate is conventionally rectangular in shape and fits within a mortised or chiseled recess in the door edge. The rectangular shape may have rounded corners for aesthetic purposes. In metal doors, a circular faceplate is conventionally used which has a plurality of serrations or ribs in its periphery and which is driven into and secured to the lateral bore in the door. Latches with these circular faceplates thus are commonly referred to as drive-in latches.
Most handles or doorknobs need to be turned approximately one-quarter of a revolution to fully retract the latch bolt to open the door, i.e. 80-90xc2x0. Some latch constructions are known which provide for full retraction of the latch bolt with a smaller rotation of the doorknob or handle. However these known constructions do not easily facilitate the incorporation of a deadbolt, the choice of faceplates, or the use of a backset adjustment that is often required.
What is needed is a latch assembly that can incorporate the advantages of an easy choice of faceplate attachments. What is also needed is a latch assembly that provides for accelerated retraction of the latch bolt during rotation of the doorknob or handle while optionally incorporating a deadbolt privacy mechanism.
In accordance with one aspect of the invention, a door latch assembly includes a latch housing having a latch bolt slideably movable from a latch position to a release position. A faceplate has an opening sized to receive the latch bolt. The faceplate has a rearwardly extending flange contoured to seat the latch housing therein.
A securement link secures the faceplate to the latch housing. Preferably the link is pivotably connected to the exterior of the housing and has a distal tip bent toward the center axis of the housing to engage a slot of the faceplate when the faceplate is seated on the latch housing to releasably secure the faceplate to the latch housing. Alternatively, the link may be pivotably secured to the faceplate, preferably at the flange, and engage a slot in the latch housing.
Preferably the securement link is in the form of a yoke with two aligned pivotable connections on opposite circumferential sides of the latch housing or faceplate. The yoke has two opposing distal tips that selectively engage two opposing slots in the other of the faceplate or latch housing.
In one embodiment, slots on opposite sides of the latch housing are aligned with the slots in the faceplate and the distal tips of the yoke are long enough to extend entirely through the slots in the faceplate and into the slots of the latch housing. Preferably, all the slots are arcuate in shape to correspond to the path that the distal tip moves in when the yoke is pivotably moved about its pivotable connection to the latch housing.
In accordance with another aspect of the invention, a latch housing for a door latch has a latch bolt slideably movable from a latch position to a release position. A securement link is pivotably connected to the housing and has a distal tip bent toward the center axis of the housing to be engageable with a slot of a faceplate to releasably secure a faceplate thereto.
In accordance with another aspect of the invention, a latch device includes a housing with an interior and an opening at one end thereof. The housing houses a bolt assembly that is biased by a spring to the extended position through the opening and longitudinally slideable in the housing against the force of the spring to a retracted position. A cam lever has a distal end that is operably connected to the bolt to move the bolt to its retracted position. The cam lever is pivotably connected to the housing. The housing also mounts a sliding actuator for reciprocal motion between a first position, which corresponds, to the extended position of the bolt and a second position which, corresponds to the bolt""s retracted position. A link member operably connects the sliding actuator to the cam lever at a position between the cam lever""s pivotable connection to the housing and the cam lever""s distal end for magnifying the bolt motion between its extended and retracted positions relative to the sliding actuator""s motion between its first and second positions.
Preferably, the sliding actuator has a planar section that is laterally disposed adjacent a rearwardly extending plate section of the bolt. The link member is disposed adjacent the planar section of the sliding actuator. The cam lever is generally disposed in the same plane as the planar section of the sliding actuator.
In one embodiment, the link has first and second protrusions in proximity to respective ends of the link. The first protrusion is received in and engages an aperture in the sliding actuator. The second protrusion is received in and engages a slot in the cam member. The planar section of the bolt has a laterally extending prong that is bent transversely from the planar section and laterally extends into the plane of the cam lever for engagement to the distal end of the cam lever. Preferably, the link is slideably movable and guided in a longitudinal recess in a fixed casing in said housing.
It is desirable that a deadbolt is disposed on one side of the latch bolt and has a parallel path of reciprocation with the latch bolt. A deadlocking slide is engaged with the deadbolt and is constructed to move with the deadbolt laterally disposed adjacent a side of the planar section of the latch bolt that is opposite from the side of the sliding actuator, link and cam lever. A blocker member is selectively actuated by the deadlocking slide to block retracting motion of the bolt.
In this fashion a compact and expeditiously assembled door latch assembly provides for an adjustment of the back set, replacement of the faceplate, accelerated retraction of the latch bolt and use of a deadbolt.